At first, the video of a man being beaten and stripped in downtown Baltimore appeared to be just another tantalizing shock clip for the Internet. But in recent days, thanks to social media users as far away as California, it could prove instrumental in solving the case.

Police have made no arrests in last month's attack, but they said tips were flooding in about the identity of the man shown punching a disoriented victim before others ripped off his clothes, took his belongings and humiliated him on the sidewalk outside a city courthouse.

Outraged viewers appear to have gone a step beyond voyeurism, using social media to identify a Rosedale man as the person who threw the punch. Meanwhile, the information helped police confirmthe identity of the victim — who had reported an assault and robbery but could not provide details at the time.

It's another example of the ways that social media are being used by police to solve crimes — or in this case, how the public can use those tools to assist police. Baltimore Police Commissioner Frederick H. Bealefeld III acknowledged that monitoring Twitter and Facebook raises thorny privacy issues for law enforcement, but said citizens are using social media in ways that can help police gain valuable information.

"If the Internet community wants to come together to give us help in an area that perhaps we don't have a great deal of expertise or resources to dedicate to, then God bless," Bealefeld said Wednesday. "It's easy to [see a video like that] and think, 'Damn, what's happening to the fabric of our society.' But to come in the next day and know that we've got leads on who the suspect is — just when you think we've left the rails, people help bring you back. That's enormously gratifying."

Anthony Mandich, 40, of Orange County, Calif., who blogged about the clip and published freeze frames and Facebook screen shots, said the video "got my blood boiling" after he first saw it on a popular message board.

"The images of [him] mugging for the camera before the humiliation began and then ... digging through the guy's pockets like it was a big joke — I really hated that," Mandich said in an interview.

His blog, which he said usually gets perhaps 100 hits a day, has pushed past 20,000. Some of the attention might be driven partly by the racial dynamic; the victim is white and the suspects are black. More than a few online commenters criticized what they saw as a lack of outrage over the Baltimore attack, even as protests continue over the shooting of Trayvon Martin, a black Florida teen whose killer said he shot in self-defense and has not been charged.

For his part, Mandich said his reaction would have been the same if the races of those in the video were reversed. Efforts to track down the people involved show the potential for a positive outcome when a violent video goes viral, he added.

"I've never seen power of the Internet so profound," Mandich said.

Police can use the help. About 88 percent of law enforcement agencies have used social media sites such as Facebook and Twitter in investigative work, according to the International Association of Chiefs of Police, which created a center to help police better employ such tools.

But uses vary widely. Police might scour the web for child sex predators or try to track spontaneous "flash mobs" by searching keywords. More commonly their efforts are likely to be reactive, such as seeking a subpoena for a suspect's Internet activity and inspecting it for evidence of a crime. More than half the agencies told the police chiefs association that they do not have policies on the boundaries of using social media.

"There's some departments and some disciplines within law enforcement very adept at using social media in appropriate ways to further investigations, but there's a lot of training that needs to go on to guide that use and make sure privacy issues are covered," said Bob Hopper, manager of the computer crimes section at the National White Collar Crime Center. "Even the younger generation [of officers] coming on, they may be intimately involved with social media but need to understand how to vet and corroborate that information so it can aid in prosecution."

Last week, a man in his 40s was arrested after police say he was depicted in a video trying to fight a teen at a Howard County school. This year, a clip was widely circulated showing a man attacking a police officer in East Baltimore; a suspect was arrested and the video will likely be crucial evidence in the case.

It is not clear when the video of the downtown beating was first posted to the Internet, but two views apparently from separate angles surfaced early this week. They were copied and uploaded to various websites where such shock clips thrive and can gain hundreds of thousands of views.

There are indications that the attackers were performing for such a potential audience. One is heard saying, "Only in Baltimore," and another mentions a website where the video would later be uploaded.

While police were troubled by the video, they said this week that they were not previously aware of the incident and needed to locate not just the suspects, but a victim.

But police soon learned they had in fact spoken with the victim about two weeks earlier.

According to police spokesman Donny Moses, he is 31 years old and from Arlington, Va., and told police March 19 that he was partying at a club at the Power Plant Live! complex the night before. The man told police that he woke up in his Mount Vernon hotel room with a black eye and scrapes and bruises all over his body. His Tag Heuer watch was missing, as well as an iPhone and the keys to his Audi.

At the time, he told police he couldn't remember what had happened or where. With the attention the video received, police have connected the dots, Moses said. Police did not release the victim's name.

Even by Internet standards, where the wildest videos get the most views, the video is shocking for its humiliation and brutality. The victim seems disoriented and is punched after he apparently tries to get back something taken from his pocket.

But something happened when the video hit Twitter: Most people were not impressed. An influential Twitter user from Baltimore who has 47,000 followers posted it and wrote, "Black Power. LMAO," an abbreviation for laughing. He included the Twitter account of the man who allegedly threw the punch.

Friends and strangers then started taking him to task. "That ... wasn't even funny. Come on now," one person wrote. "That's so ... wrong. You shouldn't even wanna admit to being in it," another said.

A man who said he threw the punch wrote back, defending himself by saying it was in self-defense.

By that time, the video had aired on television and caught fire on message boards, where insomniac posters from beyond the Baltimore area began diving into social media to determine who posted the video and who threw the punch. Soon, screenshots of a Facebook page were being matched to stills from the video and accompanied by other identifying information.

Attempts by The Baltimore Sun to reach the man were unsuccessful. Police say the investigation is continuing.